Tuning key for pianos



L. L. KORACH 'wxfums KEY FOR PIANOS Filed March '20,- 1922 2 Sheets-Sheet 1 H z I Oct. 21 1924.

L; L. KORACH TUNING KEY FOR PIANOS Filed March 20; 1 922 2 Shanta-Shut 2 Patented Oct. 21, 1924.

UNITED STATES LOUIS L. KORACH, OF CHICAGO, ILLINOIS.

TUNING KEY FOR PIANOS.

Application filled March 20, 1922. Serial No. 545,034.

T 0 all whom it may concern:

Be it knownthat I, LOUIS L. KoRAoH, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Tuning Keys for Pianos, of which the following is a specification.

My invention is an improved tuning key. It is particularly adapted for pianos but may be used on instruments, the strings of which are tuned in a similar manner as those of a piano, for instance a Z-1tl161'.' The purpose of the invention is a tuning key which the piano tuner can use with practically no instruction and a great deal of convenience.

The invention is illustrated by the accompanying figures, of which Figures 1 and 2 represent two views of one form of my invention; and

Figures 3, 4, 5 and 6 represent another form of my invention;

Of these, Figure l is an elevation, and

Figure 2 is a cross sectional elevation taken along the line 22 of Figure 1;

Figure 3 is a cross sectional elevation of the second form of tuning key;

Figure 4 is a bottom plan of the tuning igure 5 shows a section taken along the lines 55 of Figure 3 and v Figure 6 illustrates particularly the clutch mechanism in th view taken along 66 of Fi ure 3.

I shall now describe the tuning key of the form shown in Figures 1 and 2. The tuning key is provided with a framework 1, wherein is rotatively mounted a shaft 2, provided at the outer end with a handle 3. At its inner end the shaft 2 has rigidly fastened thereto a bevel gear 4 which meshes with another bevel gear 5 which is rigidly fastened to a shaft6. The shaft 6 is rotatively mounted in the framework 1, and at its outer end has rigidly fastened thereto a gear 7. This gear 7 meshes with a gear rotatively mounted in the framework 1 and which servesas an idle gear to transmit motion to a gear 9 solidly fastened to a shaft-10. The shaft 10, in its turn, is rotatively supported in the framework 1 and has rigidly fastened thereto a worm 11, which is always in mesh with the worm wheel 12 rigidly connected to a tube 13 which is rotatively mounted in the framework '1.

The train of gearing so far described serves as a reduction gearing whereby a large angular movement of the handle 3 results in a small angular movement of the tube 13. In practice the reduction from the handle to the tube is made about 30 to 1.

The tube 13 is provided at its lower end with some clutch teeth 1 Slidably and rotatively mounted in said tube 13 is a cylindrical shaft 15, which has at its upper end an extension rod 16 of smaller diameter. The rod 16 passes through a collar 17, which is screwed into the tube 13. In the space between the collar 17, the rod 16 and tube 13 is a compression spring 18 which pushes the rod 15 continually out. Rigidly fastened to the outer end of the rod 15 is a tube 19 whose inner end is provided with clutch teeth 20 adapted to engage the clutch teeth 14, and whose outer end is formed into a socket- 21 adapted to engage the pins of *the piano. Extending from and forming one portion of the framing 1 are two ears 22.

hen the tuner wishes to tune any string of the piano he takes the tuning key by the handle 3 and places the tube 19 so that the socket 21 engages the piano pin. At this moment the tube 19 is in engagement with the pin but the ears 22 of the frame 1 are above the ends of the adjacent piano pins. The tuner thereupon turns the framework 1 about the cylindrical rod 15 as an axle until the cars 22 are over aspace between the adjacent piano pins. He thereupon pushes the handle 3 inward, pushing the ears 22 between the adjacent pins of the piano, compressing the spring 18. This continues until the clutch teeth 20 come in con tact with the clutch teeth 14:. If it so happens that they intermesh, then all well and good. Ordinarily, however, they do not so mesh and the tuner thereupon has to rotate the handle 3 some angle. This he does, continually exercising pressure upon the handle 3. Then when the clutch teeth are properly placed relatively to each other, the continued pressure upon handle 3 causes them to enter into mesh. The piano tuner then proceeds to rotate the handle 3, thus rotating the engaged p in of the piano and either tightening or loosening the piano string attached thereto.

In practice it is found that the operation above described for locating the socket upon sliding down the shaft by the piano pin, the bringing of the ears 22 over a space between the adjacent piano pins, the pushing of said ears into the space between said pins, the rotation of the handle to bring the clutch 14 in alignment with the clutch teeth 20, and the engagement of said clutch teeth can be performed in a short time and becomes practically automatic.

I shall now describe the form of tuning key illustrated in Figures 3, 4, 5 and 6. The

tuning key is provided with a handle 3 which is'rigidly fastened to a shaft 2,

which is rotativelymounted in the framing of the machine. The framing is composed of several pieces; a cover piece 30, an enlargedcylinder 31 and a small tube 32. The portions 31 and 32 are Ordinarily made integral, as by casting. Extending from the tube 32 is another long tube 33, either soldered or otherwise fastened thereto and provided at its outer end with an ear 34 rigidly fastened thereto. The ear 34 has an opening 35 formed therein, which is a fairly close fit for the piano pins. The handle shaft 2 extends through the cover piece 30-wherein it is rotatively mounted 'andhas rigidly fastened on it a spider 36,

which is provided in its turn with two pla-tes 37 which serve as bearings for epi-. cyclic gears 38. There are three such gears 38 but thisis simply'a matter of convenience. One such gear would .do in theory. Each of the gears 38 double, being provided with a gear 39 at one end and a gear.

40, at the other, The epicyclic gear39 meshes with a gear 41 which is integral with the cover piece 30 and the epicyclic gear meshes with a gear 42 which is integral with a clutch piece 43. The clutch piece 43 is rotatively mounted upon the handle shaft 2 ,Thefclutch piece 43 isprevented from a pin passing through the. shaft. It is evident that the gear 41 which is integral, with the cover and plate cannot rotate. A rotation of the handle .3 causes the rotation of the spider 36and the consequent rotation of the epicyclic gear 39. This in turn causes the rotation of the epicyclic gear 40 which produces some action upon the clutch; gear 42. What that action is depends upon the relative diameters of the gears. If the gear 41 has its pitch diameter equal to the pitch diameter of gear'41 the result would be that the gear 42 would be held stationary as the handle is rotated. In practice the gear 42 has itspitch diameter made slightly larger than that of the gear 41 The rotation of the handle there-upon results in a corre- -tation of the handle:

sponding b-utmuch slower rotation of the gear 42 and in the same direction as the ro- K The mechanism thus far described,'therefore, functions as a reduction gearing totransmit the comparatively large rotation. of-the hand1e3 into a small motion of the clutch piece 43, both rotations being in the same direction.

Cooperating with the clutch 43 is a mating clutch 44. The clutches may be madein any suit-able design but I have shown them as being made with slotsin 43 and with pins 45 on 44 adapted to engage said slots. lVhenever a pin is opposite a slot the clutch pieces are in position to be against a collar .49, which in turn bears against screws 50, serves to keep the'sock'et piece 47 pushed out beyond the ear 34."

-It has been found in practice that in pianos, particularly upright pianos, there I are some piano pins very close to the sides of the piano. To conveniently reach such pins it has been found desirable to makethe tube 33 and shaft 46 quite long.

- The operation that'the piano tuner goes" through in usingthe latter described form of key is practically thesame as previously described. Repeating it: He takes the piano.

key by the handle 3, places thes ocket piece 47 uponflthe pin of the string he wishes to tune, and rotates the tuning key. about the shaft '46 until the space 35. of the ear 34 is over a convenient adjacent tuning pin. In the normal position of the parts in a tun-v ing keythe clutch pieces 44 and 43 are dis connected from --eacho,ther, allowing free relative rotation (in Figure 3 they, are

shown as in .mesh with each other). .The piano tuner then pushes the tuningkey further by'means of the handle 3, whereupon the ear 34 engages the piano pin under it, and also brings the pins 45 into contact with the clutch member 43.- If, by accident, the pins 45 are opposite spaces in the clutch member43 then these two clutch members engage. Ordinarily it happens that the pins are not-quite opposite and the piano tuner thereupon has tOwlOiifiilG the handle until the spaces of the clutch member 42 are broughtopposite the pins 45. t It will be;

seen that, on account ofthe large number;

of spaces in the clutch member 43, this preliminary rotation ofthe handle in order to cause the, clutch members toengage is but small. In practice, the reduction gearing has aratio-of about 30 to '1, as said before.-

If there are thirty teeth in the clutch mem hers, then obviously 'no more than one complete rotation .of the handle 3'can at any.

time be required as a' preliminary to en gagenient. If more spaces areput into "the clutch a smaller part of a revolution 'ofhandle 3 is required.

The form-of key shown in Figure-'3 is my preferred form. It has some advantages over that shown in Figure 1, among which theother, and it has been found easier to construct it "with a long stem than the .tuning'key of Figure 1.

1 am well aware that other piano ituning key-shave been made. I find thatsome"of them -ha've to have special mechanisms to prevent the frame of'the tuning-key from turning by getting a i purchase not upon the adjacent ,piano jpin, as in this instrument, but upon some liar or'othe'r extension. This makes them rather inconvenient'in'practice. Again, other tuning keys-have noth'ad the socket and the handle in alignment with each other, thus making it rather clumsy in placing the soQket'upOn the pi ano pin, and none of them, as faras I know, has had a clutch between the socket and the reduction gearing. lVhen the socket is placed upon the piano pin, the socket becomes fixed. It is, therefore, necessar to adjust the relation between the socket and that portion of the instrument which resists rotation (in this case the car 34.) until they are in proper position. In all piano tuning keys that I know of this had to be accomplished by a very large rotation ofthe handle. As a piano pin is four sided, this displacement at its worst might have been one quarter of a revolution, and allowing for the multiplication of movement from the socket to handle, it might have required as much as seven and one-half revolutions of said handle. This, of course, has been overcome by the introduction of the intermediate clutch members 14, 20, Figure 1 and 43, 44:, Figure 3. The final result is that I know of no other piano tuning key that is convenient to use, whereas mine is very convenient.

It has been said before that for the preliminary engagement of the clutch members with each other it is necessary to exert pressure upon the handle and rotate it.' To make this operationeasier I have provided the handle 3 with a metallic hollow 60 or 60 wherein the piano tuner may place his finger or thumb, thus making it serve as a fulcrum whereupon he may spin the handle.

The ear 34, has its opening 35, a fairly close fit for the piano pin. This form of projection is preferred to the form shown in Figure 1. The reason is, that it sometimes happens that the piano tuner will overdraw the piano wire or string, whereupon it will be necessary to reverse the direction of rotation in order to release the tension. In the form shown in Figure 1, the projection will first make contact with one piano pin and then with another different zpiano pin; thus, rotating through a rather large angle before contact is made again. Keeping in mind that this rotation is 'multipliedup through the reduction gearing, it can beeasily seen that in reversing the direction, the handle passes through quite a numbero f idle revolutions before the piano key again encountersresistance. The number of idle revolutions will'also obviously'be variableydepending upon the relative location or the piano pins. In "the form shown :in Figure 3, the opening B5 :in the car '34 enga es one fpia'no pm only, and :is as-close-afit therefor as-can beimade. The rev'ersal'of the :direction of rotationof the handle, therefore, merely swings the ear 34 from engagement with one sideof a piano pin tothe other-sideof thesanie piano pin, which is a comparatively small distance, and alsoc'omparativel-y constant.

I claim:

1. In a piano tuning-key, the combination of a handle, a reduction gearing, a clutch and a pin socket, the reduction gearing operatively connecting the handle to the clutch and producing a reduced rotation of said clutch, and the clutch being located between the reduction gearing and the pin socket, whereby the socket may be disconnected from the reduction gearing, for the purpose described.

2. In a piano tuning-key, the combination of a framework, a handle, a reduction gearing, a piano-pin socket, the reduction gearing operatively connecting the handle and the socket, a projection rigid with the frame work and located near the socket and adapted to bear against an adjacent pin, and means for holding the socket yieldingly pro truded beyond the projection, whereby the socket may be placed on a piano pin before the projection touches an adjacent piano pin.

3. In a piano tuning-key, the combination of a framework, whereon are mounted a handle, a reduction gearing, a socket, the reduction gearing operative-1y connecting the handle and the socket, a projection on the framework to bear against an adjacent pin, and elastic mechanism on the frame work to normally protrude the socket beyond the projection, whereby the socket may be placed upon its pin before the projection touches the adjacent pin.

4. In a piano tuning key, the combination of a framework, whereon are mounted ahandle, a reduction gearing, a socket, the reduction gearing operatively connecting the handle and the socket, a projection on the framework to bear against an adjacent ring. located between and operatively con-v pin, and a spring on the framework: to nor- 7 upon its pin before, the projection touches the adjacent pin.

'5. In a piano tuning-key, the comblnati'onofa handle, a socket, a reduction gearnecting the handle and the socket, and a projection located near to said socket, the projection and the socket being connected to the rest of th tuning-key by means of long intermediate pieces of small diameter for the purpose described.

6. In a piano tuning key, the combination of a framework, a handle, a reduction gearing, a clutch, a socket for a piano pin, and a projection located on the framework near the socket for" an adjacent piano pin, the reduction gearing connecting the handle and the clutch, and the clutch being operatively located between the reduction gearing and the socket, said clutch being provided with a large number of teeth, and a spring for simultaneously holding the socket protruded beyond the projection and l the tooth o-f'the clutch disconnected for the pnrposefdescribedJ I 7 1 I 7. In a piano tuning-key, the combination of a framework, a handle, a reduction gearing, aclutch, a socket for a piano pin' and a projection on the framework of the tuning-key designedto engage an adjacent piano pin, the reduction gearing connecting the handle and the clutch, and the clutch connecting the reduction gearing and the socket; the handle reduction gearing, clutch on a level with the socket. and adapted to bear against an adjacent piano pin, the socket extending farther than the projection whereby the socket may be placed on the piano pin, before the projection engages an adjacent piano pin;

In witness whereof I have hereunto set my hand and seal. 7

LoUIs L, KoRAoH] L 

